Efficient thermoelectric heat engine and Seebeck diode based on superconductor quantum dot hybrid
2nd June 2017, THEORIEKOLLOQUIUM, MC 351, Campus Duisburg, Universität Duisburg-Essen
Start: 2nd June 2017 12:00
End: 2nd June 2017 01:30 p.m.
Dr. Sun-Yong Hwang, Universität Duisburg-Essen
Fakultät für Physik, Universität Duisburg-Essen
Superconductivity has been an intriguing topic since the first
discovery in 1911. Recent interests also include creating
thermoelectric power and enhancing the heat engine efficiency.
Superconductors would be excellent candidates for generating
thermoelectric effects since they are perfect electric conductors but
poor thermal conductors deviating from the conventional Wiedemann-
Franz law. Nevertheless, the superconducting density of states
exhibits particle-hole symmetry suppressing the thermopower
generation. Therefore, a way to break this symmetry should be
devised for thermoelectric applications. We suggest that
superconductor-quantum dot hybrid setup can pave the way for
versatile thermoelectric devices. When attached to a ferromagnet,
this system can act as a thermoelectric engine with a large figure-ofmerit
ZT. Moreover, nonlinear thermocurrents of this device show
strong Seebeck and spin Seebeck diode effects with high rectification
efficiencies. Finally, in the subgap Andreev transport, interesting
cross coupling effects can appear uniquely in the nonlinear regime.
Importantly, transport properties of this device can be easily tunable
by a gate potential or a magnetic field applied to the quantum dot.